Lunch box



FIG. 1 is a top perspective view of a lunch box showing my new design;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a rear elevational view thereof; and

FIG. 6 is a front elevational view thereof. 

The ornamental design for a lunch box, substantially as shown. 